1. Field of the Invention
The present invention relates, generally, to a composite shoddy for use as a substrate. More specifically, the present invention relates to a composite shoddy for use in automotive applications and method of manufacturing same.
2. Description of the Related Art
Substrates and surface material combinations are employed in a variety of applications within the automotive industry. Substrates are widely used to provide improved aesthetic and functional quality to a surface material. By way of example, substrate and surface material combinations are used as vehicle flooring (carpeted and non-carpeted), headliners, door trim panels, dashboards, trunk area covering, and engine compartment liners among other areas known in the art.
Substrates employed in connection with automotive interiors are adapted to enhance the aesthetic appearance and/or feel of the surface material as well as to improve functional qualities of the surface material by providing sound management, vibration dampening and/or thermal insulation, among other functional qualities. For example, substrates that are commonly employed in connection with components employed in automotive interior applications have what is commonly referred to as an “A-side,” which is the side that is visible to the occupant and a “B-side,” which is the side of the surface material that faces the substrate. In the automotive field, the term “shoddy” commonly refers to one type of material used as a substrate under a surface material. Traditionally, the material used in forming a shoddy is a compilation of cloth or fibrous remnant material that is resinated, needled, or otherwise bonded together to form a flexible sheet of material. A traditional shoddy flooring substrate may possess some sound/vibration dampening, thermal insulation quality and a cushion-like feel to the flooring material. Accordingly, where a substrate possessing improved sound/vibration dampening or thermal insulation qualities is desired, application of a traditional shoddy substrate may mandate a certain thickness to achieve the desired operational qualities. Unfortunately, in the face of these requisites, the thickness of the shoddy can exceed the standards for acceptable substrate thickness, rendering a traditional shoddy substrate commercially nonviable.
One method of achieving a desired sound/vibration dampening or thermal insulation qualities while maintaining a commercially viable substrate is to combine a layer of traditional shoddy material with a layer of material capable of providing the desired qualities within a predetermined range of thickness. In these applications, the traditional shoddy may be combined with a material commonly referred to as, “mastic,” to create a composite shoddy having improved sound blocking and vibration dampening and improved thermal insulation over a traditional shoddy. As a component in a composite shoddy, mastic is constructed from a dense bituminous material, and fabricated into a weighty, yet malleable sheeting to inhibit sound/vibration. The vibration dampening efficacy of the mastic in a composite shoddy depends on its proximity to the surface material. Simply put, the closer the mastic layer is to the surface material, the greater its vibration efficacy.
A composite shoddy may be manufactured using heat and therefore are relatively warm once it has been finally formed. Following manufacture, an inventory of composite shoddy is often stored in a stacked manner to await a particular application. However, once stacked, a composite shoddy may adhere to an adjacent composite shoddy as a result of diffusion caused by the heat of manufacture, ambient temperature, and weight from the above-stacked composites, among other factors. To combat this problem, a release liner may be employed between adjacent each composite shoddy to prevent them from adhering to each other when stacked. The release liner is removed prior to employing the composite shoddy in a particular application. While release liners prevent undesired adhesion between two composites, they impose additional manufacturing steps to apply and later remove the release liner, as well as additional cost associated with materials and manufacturing the release liner itself.
Another known method to avoid the adhesion problem associated with stacking a plurality of recently manufactured composite shoddy is to immediately deploy the composite shoddy in its desired application following manufacture, thereby eliminating stacking altogether. However, this method is often limited to applications where the composite shoddy is secured to the B-side of a non-molded surface material, such as carpeting. These limited applications may require additional assembly where an adhesive is applied to either the B-side of the surface material or to the revealed mastic surface of the composite shoddy or both, to secure the composite shoddy to the B-side of the surface material. In applications where the composite shoddy is secured to a non-carpeted surface material, post-processing material shrinkage becomes an issue.
Post-processing material shrinkage refers to the reduction in size of a non-carpeted surface material as it cures or cools. The stage at which the non-carpeted surface material is formed but not yet cured is commonly referred to as, “tacky” or “green.” During the tacky stage, the non-carpeted surface is capable of bonding to the composite shoddy, thereby eliminating the additional assembly step of applying an adhesive, as described above. However, where a composite shoddy is secured to the B-side of a “tacky” non-carpeted surface material, the A-side of the non-carpeted surface material may wrinkle as a result of post-processing material shrinkage, rendering an undesirable product. To avoid the issue of post-processing material shrinkage, a composite shoddy is secured to the non-carpeted surface material only when the non-carpeted surface material has cured. However, in so doing, not only is the above-described additional manufacturing steps of applying an adhesive required, but also the additional assembly steps associated with stacking the composite shoddy are usually necessary, as well as increased product handling and providing for storage of the cooling surface material. As noted above, the release liners result in increased costs, production, and handling.
As a result, there is a need in the art for a composite shoddy having an improved composition that eliminates the need for a release liner when stacked. Further, there remains a need for a composite shoddy that accommodates for post-processing material shrinkage when secured to the B-side of a “tacky” non-carpeted surface material. Still further, there remains a need for a composite shoddy suitable for in-mold bonding to the B-side of a surface material. In addition, there remains a need for a method of manufacturing a composite shoddy that reduces costs by reducing the number of steps required to manufacture same.